Injection nozzle for internal combustion engines



K. IMFELD March 8, 1538.

INJECTION NOZZLE FOR INTERNAL-COMBUSTION .ENGINES Filed Sept. 18, 1936 Patented Mar. 8, 1938 l 2,110,365l INJECTION NozzLE Fon INTERNAL CoM- BU STON ENGINES Karl Imfeld, St. Gall, Switzerland, assigner to Societe Anonyme Adolphe Saurer, St. Gall, Switzerland, a corporation of Switzerland Application September 18, 1936, Serial No. 101,394 In Germany February 22, 1936 4 claims.

jIn order to 'secure a thorough mixture of the fuel introduced into the combustion chamber of an internal combustion engine, 'oy-means of an injection nozzle, with the combustion air which 5 is also introduced into the combustion chamber,

Injection nozzles as heretofore produced, par-- ticularly the single orifice needle jet nozzles, permit the development of a comparatively small spray angle, with the result that the desirable thoroughness .of mixture of fuel and air is not always secured. It is the object of the present A* invention to improve the construction of inj ection nozzles in such manner that the spray angle, that is, the angle at which the spray of fuel from the nozzle is directed into the combustion chamber of the engine, shall be larger than has been deemed possible heretofore, and in accordance with the invention the wall of the opening of the nozzle from which the'fuel is discharged is flared outwardly in the form of a cone toward the combustion chamber and the fuel is caused to have a. movement of rapid rotation about the axis of injection nozzle as it leaves the discharge opening. As the fuel leaves the throat of the nozzle opening, that is,

through which the fuel is discharged and where it is most restricted or has the smallest crosssection, the fuel is thrown outward, away from the axis of the nozzle, by reason of the centrifugal forceimparted by rthe rapid rotation of the fuel. Being so thrown outward, the fuel iiows along the conically flaring wall of the. nozzle opening and is thrown off at the edge of the wall in the directionof slant of the walland leaves 40' the opening in the form of a cone of spray, the

angle of such cone being substantially the same as the angle of the conical surface of the nozzle opening. By varying the angle of the conical wall ofthe nozzle opening, it ispossible to impart to the fuel spray that angle of discharge which is best adapted to the requirements of the engine with which the improved nozzle is to be used.

In an engine in which the combustion air has imiparted to it a'motion of rotary turbulence, it-

has been found that the angle ofthe -flaring nozzle opening -with respect to the axis of the in jection nozzle may be from 120 to'l50. In practice it has been found ydesirable that the outer edge of the aring nozzle opening shall be that portion of theopening sharp rather than rounded.l While one .specific means for imparting to the fuel, as it leaves the throat of the nozzle opening, a rapid rotary movement, is shown and described herein, it will be understood that such rotary movement might be 5 imparted by other known means.

AIn the accompanying drawing in which an embodiment of the invention is illustrated,

Figure l is a View in longitudinal section-of so much of an injection nozzle as is necessary to l0 enable the application thereto of the present invention to be-understood, a portion of the engine piston, with a combustion chamber formed' in its head, being indicated by broken lines. f

Figure 2 is asimilar view, in part, of the inl5 jection nozzle, but on a larger scale.

The nozzle head I, the outer end of which is arranged toproject somewhat into the combustion chamber of the engine, is shown as screw threaded internally to receive the nozzle body 2 20 which at its lower end bears tightly against the shoulder of the nozzle head. The usual nozzle. needle 4, having a limited movement within the nozzle head in an axial direction, is shown las provided with a plate flange 5 against whichl 25 bears, as usual, a spring 6 to pressv the point 1 .of the needle closely into the-seat 8 formed therefor'in the nozzle head. At a suitable distance above its point, the nozzleneedle is formed with an annular groove 9 which communicates withv y30 ,the fuel feed line, not necessary to be shown,

through a channel or channels, one of which is shown at I0, an annular channel Il formed in/ the lower end of the nozzle body 2, and a channel or channels l2, one of which is shown.- Below 35 they annular groove 9, the needle is formed with a collar'or enlargement i3 which, with the needie', has'a close working t. in the chamber 4B of the nozzle head, such collar or `enlargement'. being formed on its surface with helical grooves I4 40 .of small cross-section, such grooves serving to conduct the fuel from the space 9 to a similar space i6- below the 4collar with which the conical seat g of the needle directly communicates, the helical grooves serving to impart to the fuel as it enters the chamber I6 and as it passes therefrom i through the nozzle throat or orifice Il, a rapid rotary movement with development of substantial centrlfugal force, so that the fuel -issues from -the throat under the influence of centrifugal ac- 50 tionand vfollows and takes the direction ofthe conical wall I9 of the flaring nozzle opening I8,

which terminates in a sharp edge at 20. The fuel is thus discharged from the injection nozzle at all points about the edge 20 of the 55 I nozzle opening in the form of a 4cone of spray the valve a collar fitting the bore of the valve head which has the same angle as the conical wall l I9.'

It will be noted that the tip of the needle l entera within the throat I1, the orice ofthe'throatf beingof such diameter as will permit the flow of the proper volume of fluid when the needle is raised, the wall of the throat being preferably curved and merged into the flaring wall I3 Vof the nozzle opening IB, substantially as shown in Figure 2.

It will be understood that when the pressure of ,fluid delivered through the channels I2, II and I0 into the chamber I6 is suiiicient to overcome the resistance of the spring 6, the point 1 of the needle is'then lifted from the valve seat 8v and thefuel iiows into the chamberwith a rapid movement of rotation with development imparted by the helical grooves Il and passes thence between the needle and its seat and through the throat I'I, retaining its rapid movement of rotation, so that it follows the flaring wall I9 of the nozzle opening I8 and is discharged from the edge 20 thereof as a cone of spray.

It will be further understood that by varying the angle a of the flaring opening Il, itv is possible to adapt the nozzle to the particular requirements of the engine with whih it is used, securing that angle of discharge which is most favorable under the conditions of operation. f

I claim as my invention: v

l. In an injector nozzle for an internal com-t bustion engine, a nozzle head having a conical lvalve seat in its lower end\terminating in a discharge opening having its wall curved to form a throat, a cylindrical bore extending upward from ,the valve seat a nozzle needle movable within the bore of the nozzle having at itsv lower end a valve for the valve seat, means for imparting rotation to the fuel as it i's discharged, and yielding means for holding the valve to the valve seat.

2. In an injector nozzle, a nozzle head having a conical valve seat in its lower end terminating in a discharge opening having its'wall curved to form a throat, a cylindrical bore extending upward from the valve seat, a nozzle needle movable within the bore of the nozzle head having at its lower end a valve for the valve seat, having above and having its surface provided with helical grooves, the nomia needle being of less diameter than the collar above and below it so as to form an annular chamber above the collar and an annular chamber below it, the nozzle head having in its wall an inlet for liquid fuel leading to the chamber above the collar, and yielding means for holding the valve to the valve seat.

3. In an injector nomle, a nozzle head having a conical valve seat in its lower end terminating in a discharge opening having its wall curved to form a throat, thel nozzle head below the throat having formed therein a aring nozzle opening, a cylindrical bore extending upward from the valve 's eat, a nozzle needle movable within the bore of the nozzle head having at its lower end a. valve for the valve seat, having above the valve a collar tting the bore of the nozzle head, and having its surface provided with helical grooves.' the nozzle needle being of less diameter than the collar above and below it so as to formran annular chamber above the collar and an annular chamber below it, the nozzle head having inits wall an inlet for liquid fuel leading to the chamber. above the collar and yielding means for holding the valve to the valve seat.

4. In an injector nozzle. a nozzle head having a-conical valve seat in its lower end terminating in a discharge opening'having its wallcurved to form a throat, the nozzle head Below the throat having formed therein a flaring nozzle opening terminating in a. sharp edge, a cylindrical bore extending upward from the valve seat, a nozzleA ing of less diameter than the collar above and below it so as to form an annular chamber above the collar and an annular chamber below it, the nozzle head having in its wall an inlet for liquid fuel leading to the-chamber above the collar, and yielding means for holding the valve to the valve seat. 

